What percentage of a pond should be "deep water"? - 11/23/15 09:52 PM
What is the percentage of the total surface area of a pond that should be designed as “deep water”? This is the least productive and most expensive part of the pond depth profile to construct. However, I consider this to be the “insurance policy” for the fish in the pond. In Kansas, the fish have to survive both droughts and winter-kills due to ice cover. The USDA Pond Handbook (#590) puts my site right at the border between the 7-8’ and 8-10’ recommended minimum pond depth.
I have a spring-fed pond site in our pasture that has good clay from 4’ to at least 14’. (Soil probe truck going out next week for deeper samples.) It will be an “excavated” pond. Fortunately, due to the nature of the site - there will be no constraints at all on the depth profile or pond shape. I therefore request help from the PB denizens in designing the optimum depth profile to facilitate management of a LMB-BG pond.
The location is in south-central Kansas. Our state regulations change significantly when your water impoundment exceeds 15 acre-feet. Coincidentally, that is about how much I can afford to excavate – 15 acre-feet = 24,200 cubic yards. [The spoils will be banked just beyond the border of the pond, and then re-covered with saved topsoil.]
The initial pond design is starting with the assumption of approximately 2.0 surface acres. This yields an average depth of 7.5 feet for our design volume of 15 acre-feet.
Questions
1.) Is 10% of the surface area sufficient for a deep water pool? If things got that bad, I would try to set up emergency aeration. Would a significant portion of the fish survive a brutal July & August if they were squeezed into 1/10th of their original space?
2.) Which species drop out first as the oxygen depletes? Which size range of a given species suffers most – big fish or small fish?
3.) Which is preferred for drought insurance, a single deep basin or a narrow channel winding around the pond?
I think a narrow channel the width of a dozer blade with very steep sides would be preferred for normal fish habitat conditions. This would be one more type of “structure” in the lake and would be a deep water retreat for bass hanging out in the brush piles in shallower water. Would dozer slot walls (or even an excavator trench) stay stable over the years if they were below wave depth and were cut into clay?
4.) How deep should the pool be cut (maximum depth) for my conditions?
Considerations
The spring did not go completely dry over the past two-year drought. (Which was not that severe compared to some historical droughts.) However, the spring was only feeding a very small pond of less than 0.1 acres. Evaporation losses will go up significantly with the new pond.
The more acre-feet of water I place in the design for the deep-water pool, the more I have to shrink my surface acreage to stay within the 15 acre-feet regulatory limit.
Any recommendations or comments would be greatly appreciated.
I have a spring-fed pond site in our pasture that has good clay from 4’ to at least 14’. (Soil probe truck going out next week for deeper samples.) It will be an “excavated” pond. Fortunately, due to the nature of the site - there will be no constraints at all on the depth profile or pond shape. I therefore request help from the PB denizens in designing the optimum depth profile to facilitate management of a LMB-BG pond.
The location is in south-central Kansas. Our state regulations change significantly when your water impoundment exceeds 15 acre-feet. Coincidentally, that is about how much I can afford to excavate – 15 acre-feet = 24,200 cubic yards. [The spoils will be banked just beyond the border of the pond, and then re-covered with saved topsoil.]
The initial pond design is starting with the assumption of approximately 2.0 surface acres. This yields an average depth of 7.5 feet for our design volume of 15 acre-feet.
Questions
1.) Is 10% of the surface area sufficient for a deep water pool? If things got that bad, I would try to set up emergency aeration. Would a significant portion of the fish survive a brutal July & August if they were squeezed into 1/10th of their original space?
2.) Which species drop out first as the oxygen depletes? Which size range of a given species suffers most – big fish or small fish?
3.) Which is preferred for drought insurance, a single deep basin or a narrow channel winding around the pond?
I think a narrow channel the width of a dozer blade with very steep sides would be preferred for normal fish habitat conditions. This would be one more type of “structure” in the lake and would be a deep water retreat for bass hanging out in the brush piles in shallower water. Would dozer slot walls (or even an excavator trench) stay stable over the years if they were below wave depth and were cut into clay?
4.) How deep should the pool be cut (maximum depth) for my conditions?
Considerations
The spring did not go completely dry over the past two-year drought. (Which was not that severe compared to some historical droughts.) However, the spring was only feeding a very small pond of less than 0.1 acres. Evaporation losses will go up significantly with the new pond.
The more acre-feet of water I place in the design for the deep-water pool, the more I have to shrink my surface acreage to stay within the 15 acre-feet regulatory limit.
Any recommendations or comments would be greatly appreciated.